Fish - Starting a pond

I would like to write about our pond fish, not for the benefit of any of my readers but simply because I would like to keep a record of it for myself.
We started our pond in 2013.
In the garden of our newly purchased property, we found a disused water tank covered with a layer of flint stones. It was originally used as a water reserve in the event of fire as fire engines would not have been able to reach the property which is located near the end of a narrow lane.

So, we got to work, We opened the tank ...

 ...emptied it, cleaned it...

...and filled it with water. We then bought one water lily (at £15 the plant, it had to be only one!) and 6 water hyacinths (they were on special offer, 6 for £6, I think)...

The exciting moment was when we purchased 6 comets ( comet goldfish)...

 ... and let them free into the tank.

Things did not seem to go well after that. By the autumn, the water lily and the hyacinths had died and we saw a heron at the edge of the tank. From that day onwards, we never saw any fish and concluded that the heron had eaten them all.

What a disappointment really after all our hard work....